Conventionally, as a starting material for cloth such as woven or knitted fabric or non-woven fabric, in natural fiber field, starting materials by cultivation or farming has been used. In the chemical fiber field, it is mostly occupied by cellulose-based regenerated fiber in which natural starting material is used, semi-synthetic fiber, protein-based fiber and synthetic fiber in which coal or petroleum is used as starting material. However, recently CO2 increase due to lumbering forests for producing fibers or the like, or environmental pollution and terrestrial warming due to increase of coal- and petroleum-based industrial waste have become big problems.
For solving these problems and for terrestrial environmental preservation, research and development proceeded to change those starting materials to biomass resources (resources other than petroleum), and not only commercialization of polylactic acid fiber, PLA (polylactic acid) made from starches of corn or sweet potato, but also other developments based on bio-technology have been made rapidly. In addition, to produce fibers by cultivation, a technology for extracting fiber by mechanical methods such as slitting and splitting from bamboo, kenaf or month peach was developed and about to be commercialized. However, in this technique, although staple-fiber can be made, it is impossible to make continuation filament. On the other hand, although it is being tried to make a fiber from lees of soybean for food, it is a technique for making a staple fiber and it has not yet succeeded to make a continuous filament. Also, a fiber yarn is proposed in which Indian bamboo is spun as a cellulose rayon fiber to make a staple fiber, and it is spun to make a yarn, and, by controlling thickness and number of twists of the fiber yarn, tenseness, resilience and recovery from creases are more improved compared to woven or knitted fabric of conventional cellulose rayon fiber. JP-A-2001-115347. However, it has not been tried to take out cellulose from bamboo and make it into filament for fabrics such as woven, knitted and nonwoven fabrics.
Although, there is a publication describing about obtaining a textile by mixing a polyester type synthetic fiber to a staple fiber yarn made from bamboo and it is effective for stretchability and touch, but a filament yarn is not indicated. JP-A-2003-113554.
This disclosure makes it possible to industrially produce a cellulose-based filament by removing impurities such as resin component and ash component to thereby take out the cellulose component with a good purity. And, using the filament made by this new technology, this disclosure makes it possible to make a fabric made thereof such as woven or knitted fabric or nonwoven fabric.